1. Field of the Invention
The present invention relates to a measuring endoscope system for forming two images of an object to be measured, which are taken by two objective lenses, at different positions on an imaging device incorporated in a main endoscope unit, processing the data of the endoscopic images, and carrying out measurement.
2. Description of the Related Art
A stereoscope endoscope using one CCD has been disclosed in Japanese Unexamined Patent Publication No. 64-26813 in the past. Japanese Unexamined Patent Publication No. 62-80768 has disclosed a means for correcting geometric distortions in images produced to realize stereoscope by utilizing a parallax caused by observing an object from right and left points, and for upgrading the level of matching from coarse matching performed at a low resolution to matching performed at a high resolution by predicting relative distortions in the images for realizing stereoscope.
Although the Japanese Unexamined Patent Publication No. 64-26813 has disclosed a stereoscope endoscope utilizing one CCD, no mention is made of a means for measuring an object.
The Japanese Unexamined Patent Publication No. 62-80768 has disclosed a technique for correcting geometric distortions in images for realizing stereoscope and grading the level of matching from coarse matching performed at a low resolution to matching performed at a high resolution by predicting relative distortions in the images for realizing stereoscope, but it has not described a measuring method which takes into account the uncertainty in the characteristics of lenses which occurs when one optical adaptor is exchanged for another.
A known stereoscopy measuring apparatus comprises two imaging systems which take images for realizing stereoscope, a capture circuit for fetching the data of the stereoscopic images into a computer, and a computer for processing the image data. The two imaging systems may be realized with two independent cameras or may be, as described in the Japanese Unexamined Patent Publication No. 64-26813, realized with one imaging device for imaging the stereoscopic images.
This kind of stereoscope measuring apparatus cannot achieve measurement with high precision unless distortions in images caused by lenses are dealt with. The lenses cannot therefore be heedlessly replaced with new ones. Even when a stereoscopic measurement method is adapted to an endoscope, it is preferred that a plurality of types of optical adaptors are made available for alternate use so that not only stereoscopic measurement can be performed, but also observation through a single lens can be achieved. However, for stereoscopic measurement, an endoscope dedicated to stereoscopic measurement must be employed because of the image distortions caused by the lenses.
Normally, optical adaptors are different from one another in terms of optical characteristics. Moreover, the position of a CCD incorporated in a main video endoscope unit is uncertain. The uncertainty can be a cause of critical error in measurement. For eliminating the error, it is necessary to associate the optical adaptors used for measurement with video endoscopes on a one-to-one basis, acquire optical data, and correct image data.
However, if a video endoscope is put on sale in combination with an associated optical adaptor used for measurement, a user who does not intend to carry out measurement procedures will find the endoscope expensive because of the unnecessary optical adaptor for the user. However, if a video endoscope is not marketed in combination with an associated optical adaptor used for measurement, problems arise that an optical adaptor used for measurement cannot be additionally purchased and used in combination with a main video endoscope unit.
On the side of a manufacturer, there is a problem that since an optical adaptor must be attached to a main video endoscope unit in order to acquire data, a manufacturing process becomes complex and cost increases accordingly. Consequently, the measuring endoscope system is expensive for users.